This invention relates to a method and apparatus for facilitating interaction between a home subscriber server (HSS) and a home location register (HLR) in a legacy network. More particularly, the invention provides a technique and system to allow home subscriber servers (HSSs) to retrieve a subscriber's dynamic location/state information from a legacy home location register (HLR). For example, a mobile application part (MAP) operation ATI (AnyTimeInterrogation) messaging technique may be used by the home subscriber server (HSS) to query the legacy home location register (HLR) and obtain the requested location/state information.
While the invention is particularly directed to the art of facilitating interaction between a home subscriber server (HSS) and a home location register (HLR) in a legacy network to retrieve state or location information, and will be thus described with specific reference thereto, it will be appreciated that the invention may have usefulness in other fields and applications. For example, the invention may be used in other implementations of new network elements in a legacy network.
By way of background, legacy networks include functionality that is useful for determining location and/or state information for particular mobile subscribers. For example, with reference to FIG. 1, a portion of a network 10 is shown. As illustrated, the network includes a service control point (SCP) 12 that communicates with a home location register (HLR) 14. Also shown is a visitor location register (VLR) and/or a serving GPRS (General Radio Packet Service) support node (SGSN) 16.
When a request for a location or state of a mobile station is, received by the service control point (SCP) 12, it typically sends a request for that information to an appropriate home location register (HLR) 14 in the form of a mobile application part (MAP) message (e.g. an AnyTimeInterrogation (ATI) request). The home location register then communicates with the visitor location register (VLR) and/or a serving GPRS (General Radio Packet Service) support node (SGSN) 16 to retrieve the requested information using standard messaging techniques (e.g. mobile application part (MAP) ProvideSubscriberInfo (PSI) requests and responses). The home location register (HLR) 14 ultimately sends the requested information back to the service control point (SCP) 12 using mobile application part (MAP) messaging (e.g. an AnyTimeInterrogation (ATI) response).
The 3GPP standard (e.g. 3GPP Sh standard TS23.002) specifies the implementation of home subscriber servers (HSSs) to replace the legacy home location registers (HLRs). To do so, the standard mandates that the functionality of the home subscriber servers (HSSs) include the legacy home location register (HLR) functions. The home subscriber servers (HSSs) are also required to provide Internet (or IP) media subsystem (IMS) functions. This is illustrated in FIG. 2, where a home subscriber server (HSS) 10 includes a first module 22 for implementing internet multimedia subsystem (IMS) functions and a second module 24 for implementing home location register (HLR) functions.
In this environment, a home subscriber server (HSS) receives a location/state query from an application server (AS). Then, the home subscriber server (HSS) sends a mobile application part (MAP) ProvideSubscriberInfo (PSI) request, based on information available to the home subscriber server (HSS), directly to the subscriber's visitor location register and/or serving GPRS support node (VLR/SGSN) to get the location/state information.
In implementation, however, many service providers wish to maintain legacy home location registers (HLRs) and purchase home subscriber servers (HSSs) that do not function as home location registers (HLRs). The home subscriber servers (HSSs) of this type still perform Internet multimedia subsystem (IMS) functions. But, the home subscriber server (HSS) in this form does not maintain or have available to it the subscriber's visitor location register and/or serving GPRS support node (VLR/SGSN) number—which cannot be statically provisioned. As a result, the home subscriber server (HSS) of this type needs to be able to retrieve a subscriber's dynamic location/state data from a home location register (HLR) to fulfill any queries from, for example, an Internet media subsystem (IMS) application server (AS).
However, because the current standard presumes that the home location register (HLR) functions will be integrated into home subscriber server (HSS), there is no standard interface defined between a home location register (HLR) and a home subscriber server (HSS). Therefore, there is an inconsistency between a desired implementation of the standards and that which is contemplated by the standards.
The present invention contemplates a new and improved system that resolves the above-referenced difficulties and others.